Lining of pipelines or passageways using a push rod adhered to rod and liner

ABSTRACT

The lining of lateral pipelines is effected from the service end by inserting a resin impregnated lining tube into the lateral using a push rod. The leading end of the push rod is attached to the liner by a relaeasble device so that once the liner is in place, and the rod pulled back, the liner detaches and remains in the lateral. The liner is held in folded state by straps which are broken as the rod is pulled back in that a rope attached to the leading end of the rod is trapped under the straps and breaks them one by one as the rod is retracted.

This invention relates to the lining of pipelines and passagewayswherein a liner tube is fed into the pipeline or passageway, and then isinflated onto the pipeline or passageway surface. The liner, which is aflexible tubular structure, includes a layer of resin absorbent materialsuch as a fibrous felt which is impregnated with a curable syntheticresin, and the basis of the lining operation is that when the liningtube is inserted and inflated up to the size of the inner diameter ofthe pipeline or passageway, the resin is cured so that the flexibleliner turns into a rigid lining lying on the pipeline or passagewaysurface.

This basic technology is now extremely well known, and is practicedthroughout the world. The basic idea related to this lining operation isdisclosed in U.S. Pat. No. 4,009,063, which discloses that the liner ispulled into the pipeline or passageway and then is inflated using afluid medium such as air or gas or even a liquid such as water.

U.S. Pat. No. 4,064,211 discloses a modification of the basic idea andin this U.S. patent it is suggested that the liner after impregnationshould be everted into and along the passageway using a liquid toperform the eversion and to provide a means whereby the inwardlytravelling portion of the liner is buoyantly supported before reachingthe everting face.

Modified methods for the insertion and inflation of the liner have alsobeen proposed in the past, and for example in the paper entitled"Inflatable Terylene Reinforced Resin Pipe Linings" by D Rhys-Jonespresented at the First International Conference on the internal andexternal positions of pipes on Sep. 9-11th, 1975 at the University ofDurham, England, it is disclosed that the liner may be pulled into thepipeline or passageway, and then an expansion tube or hose is evertedinto the liner when it has been pulled into the pipeline or passagewayand when it is still flexible and flat, in order to inflate the liner upto the pipeline or passageway surface. An advantage of this method whichis identified by the description pull-in and inflate is that theexpansion tube which is used can be of relatively light weight so thatair can be used as the medium for expanding the liner. Additionally, theexpansion tube or hose can be withdrawn from the pipeline or passagewayafter the resin of the liner has cured and the liner has turned into arigid lining, so that the expansion tube or hose can be reused.

In U.S. Pat. No. 4,786,345, it is explained how this pull-in and inflatesystem can be used in connection with the lining of what are calledlateral pipelines or passageways, being the service pipes which leadfrom for example domestic dwellings or office buildings to a main lineunderground sewer.

In the lining of these lateral pipes, difficulties arise because it isnot easy to position the liner inside the lateral pipe from inside themain sewer, although a number of attempts have been made to do this asindicated for example in the following patent specifications:

U.S. Pat. No. 4434115

PCT No. GB92/02287

EPA No. 0526521

The present invention is concerned with a method of inserting resinimpregnated flexible tubular liners into pipelines and passageways, andin particular those pipelines and passageways such as lateral pipeswhere access to one end of the pipeline or passageway is difficult.

In accordance with the present invention there is provided a method oflining a pipeline or passageway by means of a length of flexible tubularliner which comprises or includes resin absorbent material which isimpregnated with a curable synthetic resin comprises attaching one end,(the leading end). of the liner to one end, the (leading end) of aninsertion rod means so that by pushing the rod, leading end first, fromone end of the pipeline or passageway to be lined, to the other end ofthe pipeline or passageway, causes the liner to be pulled into thepipeline or passageway, and wherein the said leading end of the rod isconnected to the leading end of the liner by a means enabling the rod topull the liner into the pipeline or passageway, but when the rod isretracted after the liner is so placed in the pipeline or passageway itwill become detached from the liner leaving the liner in position.

Additionally, it is preferred that connected to the leading end of therod is a rope, cable or the like which extends from the leading end ofthe rod, when it is at the remote end of the pipeline or passageway,back to the insertion end of the pipeline or passageway, and said rope,cable or the like is trapped under restraining means which serve to holdthe flexible liner in a folded condition to which it is moved prior toinsertion into the pipeline or passageway, and said rope, cable or likeserves to break or sever said holding means when the rod is retractedfrom the pipeline or passageway enabling the liner subsequently to beexpanded.

The said holding means preferably comprises tapes or straps which arewrapped around the folded liner. The tapes or straps may be adhesive innature, and may be applied at spaced intervals. The said tapes or strapspreferably are of a nature so as to have good tensile strength in thedirection of the length of the tapes or straps, and poor tear strengthin a direction at right angles to the length of the tapes or straps sothat they will tear readily by virtue of the rope, cable or the likeeffecting a tearing force thereon as the rod is pulled back out of thepipeline or passageway.

The leading end of the rod may be provided with a head with a groove torecieve a retaining strip which is adhesive in nature, said strip beingadhered to the leading end of the liner, and being wrapped around thesaid head and anchored in relation to the leading end of the rod. Bythis means, the strip will serve as a pulling means when the rod isforced into the pipeline or passageway to pull the lining tube alongwith a rod into the pipeline or passageway, but when the rod isretracted after insertion of the liner, the said strip will peel awayfrom the liner leaving it in position.

Where the pipeline or passageway is a lateral pipe connection, the headon the rod may be such as to contact the opposite side of the main sewerpipe when the rod is fully inserted, which will ensure the accuratepositioning of the liner in relation to the lateral pipe.

When the lateral pipe has been inserted, and the rod has been retracted,the lining may be inflated up to size by means of an expansion tube orhose which can be everted directly into the liner accurately in place inthe pipeline or passageway.

The expansion tube or hose may be everted into the pipeline orpassageway using any suitable fluid such as a gas or liquid or acombination of same, but regardless of the fluid used, the liner will beheld in the inflated condition on the pipeline or passageway surfaceuntil curing of the resin takes place.

Equally, the liner may be of any suitable construction as long as it isprovided with at least one layer of resin absorbent material which isimpregnated with curable synthetic resin which can be cured or will curewhen the liner is inflated onto the pipeline or passageway surface.

An embodiment of the present invention will now be described, by way ofexample, with reference to the accompanying diagrammatic drawings,wherein;

FIG. 1 shows a sectional elevation of a known flexible linerconstruction, which is suitable for use in connection with the methodhereinafter described;

FIG. 2 shows the leading and trailing ends of the liner of FIG. 1 withthe insertion apparatus coupled thereto;

FIG. 3 shows an initial stage of the operation of inserting the linerinto a lateral pipeline;

FIG. 4 shows the completion of the insertion operation;

FIG. 5 shows how the insertion apparatus is retracted and the functionit performs in this retraction, leaving the liner in place ready to beinflated;

FIG. 6 is a perspective view showing the inner end of the liner and theinsertion apparatus in the course of being retracted;

FIG. 7 shows the liner when placed in the lateral pipeline and in thecourse of being inflated to form the final lining;

FIG. 8 shows the trailing end of the liner when inflated onto thelateral passageway surface; and

FIG. 9 shows the leading end of the liner when similarly inflated.

Referring to the drawings, and firstly to FIG. 1, a flexible tubularliner 10 has the configuration shown and comprises an inner layer 12 ofresin absorbent material such as a needled felt in one or more layers,and to the outside of the absorbent material is an integral impermeablecoating 14 comprising for example polyurethane film or the like. Theliner in this condition is flexible, and although the layer 12 isthoroughly impregnated with a curable synthetic resin, the liner remainsflexible until the resin cures. It is shown in a flattened conditionwhich is the normal form it will take, but when it is applied to apipeline or passageway surface, it is inflated into circular form or tothe form of the passageway cross section.

In this method, the liner 10 is open at each end, and it is specificallyfor insertion into a lateral pipeline or passageway 16 as shown in FIG.3 which extends from ground level through a service connection 18 (whichmay be the inside of a domestic dwelling) to a main line undergroundsewer 20. The lateral passageway 16 is shown in this case as having twobends, but it may be straight or it may be curved or have a smaller orgreater number of bends.

The liner 10 is dimensioned to the size of the lateral passageway 16which it is to line, and in this embodiment, the liner 10 is in factfolded as shown in FIG. 1 by dotted lines into a U-shaped configuration.Before it is so folded however, at one end, the leading end, which isillustrated by reference numeral 22 in FIG. 6, has the outer film 14provided with slits 24, so that the said end can flare bell-like whenthe liner is inserted as will be explained hereinafter. Additionally, atthe leading end 22, at the extremity thereof there is applied by anysuitable means a terminal strip 26 which locks into the main sewer pipe20 as will be explained, and spaced from the strip 26 is applied asealing ring 28 which may be a hydrotite sealing ring to seal againstthe surface of the pipeline or passageway 16 and to prevent roots fromgrowing along the interface between the liner and the passagewaysurface.

The trailing end which is illustrated in FIG. 2 by reference numeral 30is provided with a similar sealing ring 32 which is spaced inwardly ofthe extremity of the end 30.

The strip 26 may be applied by any suitable aggresive adhesive to ensurefirm anchorage to the outer surface of the liner 10.

To the leading end 26 of the liner is further attached an insertionapparatus of which the main elements are shown in FIG. 2. This apparatuscomprises a strap retaining ball 34 which has a circumferential anddiametrically arranged groove 36 in which is received a glass fibre tapelength 38 having adhesive on each side thereof. The tape 38 lies in thegroove 36 and is adhered to the ball 34, but in addition an end 40 ofthe tape 38 is applied to the outer surface of the liner 10 so as toadhere thereto. This length 40 lies inside the liner when it is formedto U configuration as shown in FIG. 1.

The ball 34 is carried on the end of an insertion rod 42 which isscrewed to the ball at 44 as shown. The rod 42 may be made up in lengths42A, 42B which are screwed together so that the rod can be of anysuitable length for pushing the liner into position. It is appreciatedthat the rod 42 must be capable of applying a considerable thrust forceto insert the liner into the pipeline or passageway, but also must be ofsufficient flexibility so that it can follow the contour of the curvesin the passageway 16.

The rod 42 is at least as long as the liner, and preferably longer as itwill be manipulated from ground level to push the liner into position aswill be described hereinafter.

Finally, attached to the leading end of the rod 42 is a pull back rope46 which is attached to the rod 42 by cable ties or adhesive strips 48or the like.

The pull back rope 46 lies in the inside of the U formed by folding theliner as shown in FIG. 1, and is also shown in FIG. 2, and finally theliner 10 is held in U-shaped configuration by means of retention tapes50 which are of a nature having good longitudinal strength, butrelatively poor transverse tear strength so that as will be explainedhereinafter, the rope 46 can cut through the tapes 50 to release themwhen the lining tube 10 has been placed in position.

At the trailing end 30, the rope 46 is folded back on itself as shown inFIG. 2, and at its extremity it is provided with a holding knot 52.

FIGS. 3, 4 and 5 illustrate the insertion method diagrammatically. Theleading end of the liner tube when folded as shown in FIG. 2 is insertedinto the pipeline or passageway 16 from the service connection 18 bypushing on the rod 42 by indicated by arrow 54. The ball 34 is theleading element in this insertion process, and by virtue of the force onthe rod 42, indicated in dotted lines in FIGS. 3, 4 and 5, and throughthe medium of the pull tape 40, the liner is forced into and along thepassageway 16. FIG. 4 shows the liner fully in position, and it will beappreciated that its length dimension is such as to cover the surface ofthe liner to be lined. FIG. 4 also illustrates that a hold back rope 56may be attached to the trailing end of the liner in order to control thein-feed of the liner so that it does not "run away" under the effects ofgravity and so that it can be pulled back if necessary.

When the liner is in position as shown in FIG. 4, it is simply a matterof pulling the rod 42 rearwards, which has the effect of pulling backthe rope 46 in a manner such that as illustrated in FIG. 6, the ropefolds back upon itself. A number of effects take place at the leadingend of the liner and the first is that the rope 46 cuts through thefirst retention tape 50 as shown in FIG. 6, and then the end of theconnecting strip 40 is peeled away from the leading end of the liner.Arrow 56 in FIG. 6 illustrates the direction in which the rod 42 ispulled back. As the rod continues to be pulled back so it breaks thetapes 50 sequentially, and FIG. 5 shows the rod 42 retracted rearwardlyby approximately half the length of the passageway 16 to be lined. Therod 42 is simply continued to be pulled rearwardly so that all of theholding tapes 50 are severed, and the liner is now in position ready tobe inflated.

The rearmost holding tape 50 may be double wrapped in order to retainthe folded over portion of the rope 46, which facilitates the breakingopen of the last holding tape and the retention of the rope end.

The assembly is in fact made up in the form described under factoryconditions, and can be delivered to site, or assembly can take place onsite.

Where appropriate and where possible, the leading end of the liner tube10 may be provided with a pull rope which leads through the main sewerand to a location where pulling can take place in order to assist thein-feed of the lining tube 10.

When the lining tube is being inserted, if the passageway 16 does have anumber of bends as illustrated, insertion may be assisted by a pull-inrope as described, and a remote controlled camera may be utilized forchecking when the lining is in the correct position. These areestablished techniques. Some bouncing or back and forth thrusting of thepush rod may be required in order to assist the insertion process shouldit be that the lining and push rod become locked or frictionally stuckagainst the passageway surface.

When the lining is in position as illustrated in FIG. 5, it then has tobe inflated as shown in FIG. 7. This inflation procedure is in factconventional insofar as an inflation tube 60 is everted into and alongthe inside of the lining tube 10 as shown in FIG. 7. The inflation tubeis dimensioned and inflated so that when the inflation step has beencompleted, as shown in FIG. 9, the leading end of the inflation tube 60projects into the main sewer 20, thereby flaring the leading end of thelining tube 10 as shown in FIG. 9. The strip 26 which is applied to theoutside of the lining tube 10 as described in relation to FIG. 6therefore forms an anchor or catch on the surface of the main sewer 20so that an effective positioning and location of the lining tube 10 isachieved. Said strip 20 incidentally may comprise a strip of feltmaterial which itself is impregnated with a curable synthetic resin, sothat a hard collar will eventually form in the vicinity of the junctionbetween the lateral passageway and the main sewer 20. The trailing endof the inflation tube 60 is in fact belled out to give the effectdescribed.

The said trailing end of the inflation tube 60 further has a shackle orlike coupling 62 connected thereto, and a pull back rope 64 is connectedto the shackle. When the lining operation has been complete therefore,the inflation tube 60 which may comprise a silicone coated fabric hose,can be pulled back so that the hose inverts and is peeled away from thecured lining.

Where the resin is of a type which cures naturally i.e. it is an ambientcure resin, the inflation medium for the tube 60 may be any suitablesuch as air or water, but should it be that the resin requires heat toinitiate and/or effect its cure, then a heated inflation medium shouldbe used. Such medium may comprise hot water or steam or any othersuitable fluid medium. The fluent medium may be inserted by any suitableapparatus and structure erected at ground level and it may assist in theperforming of the inflation if the inflation tube is everted part wayinto the trailing end of the lining tube before it is folded andassembled and inserted as described in relation to FIGS. 3 to 5.

Where hot water is used for the inflation, it may be hot water at a 160°C. which is used in conjunction with a silicone inflation tube. Asuitable pumping apparatus may be adopted for example as described inour co-pending U.K. Patent application filed Dec. 16, 1993 and theinflation tube may require to be bounced so as to assist the inflation,by cyclically varying the pressure level inside the inflation tube. Itis to be noted that control of the inflation tube should be effected sothat it does not "run away" during the inflation operation. When theinflation tube has been fully inserted, the hot water is maintained inthe inflation tube, and maybe circulated if desired, to maintain thetemperature, until the resin in the lining tube has cured sufficientlyhard so that the lining tube forms a cured hard lining which remainsfirmly in position when the inflation tube is removed.

FIG. 8 shows the trailing end of the lining tube when inflated, andillustrates how the hydrotite sealing ring 32 forms a seal against thepassageway surface. FIG. 9 illustrates how the leading end sealing ring28 also seats against the pipeline or passageway surface.

If the inflation tube is simply inserted by pouring water into asuitable header apparatus, the insertion tube may be held back manually,and various push rods may be used for bouncing the tube to effect theefficient inflation of the inflation tube inside the liner tube.

Instead of using an inflation hose which is inverted into the liningtube to inflate same, an inflation tube or bladder may be providedinside the lining tube before it is inserted in the passageway. Afterinsertion, the bladder is inflated to apply the lining tube to thepassageway surface and then the bladder is peeled away by a pull backrope or the like connected thereto and removed from the passageway, forexample as set forth in International Patent Application No WO 93/16320.

The invention provides an extremely effective insertion method for resinimpregnated liner tubes, especially those tubes which are to linepassageways such as lateral passageways, or "blind" passageways whereaccess to the remote end of the passageway is impossible of difficult.

What is claimed is:
 1. A method of lining a pipeline or passageway bymeans of a tubular liner, comprising:a) attaching one end (the leadingend) of the tubular liner to one end (the leading end) of a push rodmeans by a a length of an adhesive retaining strip adhered to theleading end of the push rod means and to the leading end of the liner;b) inserting the liner in the pipeline or passageway by pushing the rodmeans leading end first into and along the pipeline or passageway from anear end to a distal end of the pipeline or passageway so that the rodmeans pulls the liner into the passageway, c) pulling the rod means inan opposite direction to release said adhesive retaining strip wherebythe rod means is pulled from the pipeline or passageway and the linerremains in position, and d) inflating the liner into the pipeline orpassageway to line same.
 2. A method according to claim 1 wherein theliner is a length of flexible tubular liner which comprises or includesresin absorbent material which is impregnated with a curable syntheticresin and the method includes the step of curing the resin whilst theliner is inflated.
 3. A method according to claim 1, wherein theadhesive retaining strip is a length of adhesive tape.
 4. A methodaccording to claim 1, wherein the liner is folded in two prior to beinginserted in the pipeline or passageway and is held in such condition bystrap means wrapped therearound and spaced therealong, and the strapmeans are broken by a rope means trapped under the strap means in thatthe rope means is attached to the leading end of the rod means and isretracted with the rod means, breaking the strap means as it isprogressively removed from the pipeline or passageway.
 5. A methodaccording to claim 1, wherein the liner is folded in two prior to beinginserted in the pipeline or passageway and is held in such condition bystrap means wrapped therearound and spaced therealong, and the strapmeans are broken by a rope means trapped under the strap means in thatthe rope means is attached to the leading end of the rod means and isretracted with the rod means, breaking the strap means as it isprogressively removed from the pipeline or passageway.
 6. A methodaccording to claim 1, wherein the liner is inflated by everting aninflation tube into and along the inside of the liner.
 7. A methodaccording to claim 4, wherein the liner is inflated by everting aninflation tube into and along the inside of the liner.
 8. A methodaccording to claim 5, wherein the liner is inflated by everting aninflation tube into and along the inside of the liner.
 9. A methodaccording to claim 1, wherein the leading end of the liner is flaredoutwardly into the main passageway by the inflation step.
 10. A methodaccording to claim 1, wherein the leading end of the liner is providedwith a sealing member at the juncture where the lateral pipeline orpassageway meets a main pipeline.
 11. A method according to claim 10,wherein the leading end of the liner having the sealing member is flaredoutwardly into the main passageway by the inflation step.
 12. A methodaccording to claim 1, wherein seals are formed between the pipeline orpassageway and the ends of the liner by sealing rings on the outside ofthe liner.
 13. A method according to claim 1, wherein the length of therod means is increased by the addition of sections thereto as it ispushed into the pipeline or passageway.
 14. Apparatus for inserting atubular liner having a leading end and a trailing end in a pipeline orpassageway comprising:a) rod means having a leading end and a trailingend b) a length of adhesive retaining strip adhered to the leading endof the rod means and to the leading end of this liner, said rod andstrip adapted to pull the liner into the pipeline or passageway when therod means is pushed into the pipeline or passageway and to release theliner, to leave it in the pipeline or passageway when the rod means ispulled from the pipeline or passageway.
 15. Apparatus according to claim14, wherein the releasable adhesive retaining strip is a length ofadhesive tape for attachment to the leading end of the rod means to theleading end of the liner.
 16. Apparatus according to claim 14, whereinsaid rod means comprises a number of rod sections connected together endto end.
 17. Apparatus for use in lining a pipeline or passagewaycomprising:a) a length of tubular liner having a leading end and atrailing end, said liner folded lengthwise and held folded by strapmeans round about the liner at spaced intervals along the lengththereof; b) rod means having a leading end and a trailing end, saidliner and rod means lying side by side, c) releasable attachment meansconnecting the leading end of the rod means with the leading end of theliner, said releasable attachment means adapted to pull the liner intothe pipeline or passageway when the rod means is pushed into thepipeline or passageway and to release the liner, to leave it in thepipeline or passageway when the rod means is pulled from the pipeline orpassageway; and d) a fracturing rope extending along the liner andpositioned under the strap means, the rope connected to the rod means atthe leading end thereof.
 18. Apparatus according to claim 17, whereinthe liner is a length of flexible tubular liner which comprises orincludes resin absorbent material which is impregnated with a curablesynthetic resin.
 19. Apparatus according to claim 18, wherein thereleasable attachment means comprises a member carrying adhesive tapewhich is attached to the liner.
 20. Apparatus according to claim 19,wherein the member comprises a ball having a groove thereon receivingsaid tape.
 21. Apparatus according to claim 17, wherein said rod meanscomprises a number of rod sections connected together end to end.